1. Field of the Invention
The disclosure generally relates to offshore foundations. More particularly, the disclosure relates to anti-scouring structure and methods for the offshore pile foundations, such as for offshore wind turbines.
2. Description of the Related Art
Currently seabed scour can significantly affect support foundations installed in the seabed when exposed to rapidly moving water or other liquids. The seabed scour erodes away support material, significantly weakening the support foundation.
FIG. 1 is a side view schematic diagram illustrating a prior art pile foundation. FIG. 2 is a side view schematic diagram illustrating the prior art pile foundation that has been subjected to erosion from seabed scour. A typical example of a foundation would be a pile 1 installed into the seabed 2. The pile 1 Is generally a monopole. The pile 1 can be used to support an offshore wind turbine and other structures and functions. The seabed scour weakens the foundation of the pile, if not countered in some fashion.
More specifically, the pile 1 is designed for a certain amount of support, such as for a mast of the wind turbine, when driven into the seabed, where a certain length “L1” of the pile is surrounded by soil 3. However, the seabed scour erodes the soil 3 and other material from around the pile and effectively reduces the length in the soil to a length “L2” by an amount of an erosion distance “X”. Sometimes, the seabed scour can occur relatively quickly, so that the soil is already scoured before the wind turbine or other structure can be coupled to the pile or within a few months after installation. Thus, the designed stability is compromised and weakened.
Traditional methods of countering seabed scour apply rock material around the base of the foundation to stabilize the seabed and prevent further erosion. However, rock dumping is expensive and requires a local source of rock material. It is common for the rock dumping to be sorted and graded into different sizes and applied as layers, further increasing the expense.
There remains a need for an improved system and method to minimize the seabed scour around a seabed foundation.